JP2012243697A - Spark plug controlling guage, plug hole controlling guage of cylinder head, and guage set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plug control guage and a plug hole control guage suitable for controlling an outside electrode so as to always have a specific direction when a spark plug is mounted to a plug hole.SOLUTION: A ring-shaped guage 40 is used for controlling a plug on which a rotational direction phase at the thread cutting start position of a male screw part and relative positional relation between the rotational direction phase and a direction of the outside electrode are specified. Two face width parts 42 for instructing the direction of the outside electrode when fastening the guage to the male screw part of the plug with specified torque are formed. Similarly, in a screw shaft-shaped guage 43 for a plug hole on which a rotational direction phase at the thread cutting start position of a plug hole side female screw part is specified in advance, two width parts 45, 46 for instructing the direction of the outside electrode are formed.

Description

  The present invention relates to a spark plug management gauge for managing the rotational direction position of a spark plug attached to a cylinder head of an internal combustion engine (engine), and a female screw in a plug hole on the cylinder head side to which the spark plug is attached. The present invention relates to a plug hole management gauge for managing the threading start position of each part, and a gauge set comprising a combination of both gauges.

  As is well known, a spark plug (hereinafter simply referred to as a “plug”) that is mounted on a cylinder head of an internal combustion engine (engine) has its male threaded part on the side of the metal shell side of the female threaded part on the plug hole side. By screwing (screwing), it is fixed via a gasket so that the tip end side faces the combustion chamber. In that case, the direction (rotation direction position) of the outer electrode (ground electrode) that faces the combustion chamber and makes a pair with the center electrode is identified from the viewpoints of eliminating variations in combustion among cylinders, improving ignitability, and improving fuel efficiency. There is a request to match the direction.

  As a countermeasure, for example, a spark plug manufacturing method using a spark plug manufacturing male screw jig as described in Patent Document 1 has been proposed. In the technique described in Patent Document 1, when the male screw jig is screwed into the plug hole on the cylinder head side, the position of the outer electrode that can provide optimum ignition performance of the engine, and the origin position of the male screw jig The threading phase angle range α is specified between Furthermore, when the female thread jig is screwed onto the male thread part on the spark plug side, it corresponds to the threading phase angle range α that has already been specified using the male thread jig based on the origin position on the female thread jig side. The position where the outer electrode is joined or the expected joining position is determined as the joining phase angle range α0.

JP 2002-141156 A

  However, in the technique described in Patent Document 1, each time the external electrode arrangement selection position and the threading phase angle range α on the plug hole side of the cylinder head are used, even if a male screw jig and a female screw jig are used. In other words, the position of the joint on the outer electrode on the plug side is specified in the form of so-called actual matching, so that it is not possible to efficiently produce spark plugs. It will be.

  In many cases, such a method is necessary without completely managing the rotation direction phase of the female screw start position in each of the plug holes on the cylinder head side, that is, the thread cutting start position of the female screw part. This is because it is not constant.

  Therefore, the quality of the plug is managed so that the rotational direction phase of the threading start position of the male thread on the plug side and the relative positional relationship between the rotational direction phase of the threading start position and the direction of the outer electrode always have a specific positional relationship. On the other hand, if the quality of the plug hole is controlled so that the rotational direction phase of the threading start position of the female thread part on the plug hole side that is screwed to the male thread part on the plug side is always at a specific position, This eliminates the need for a method and enables efficient production of plugs.

  The present invention has been made paying attention to such a problem, and in response to a request to always adjust the direction (direction) of the outer electrode of the plug to a specific direction, threading of the male threaded portion on the plug side is started. The rotational direction phase of the thread and the rotational direction phase of the threading start position of the female thread part on the plug hole side is always a specific positional relationship with the rotational direction phase of the position and the relative positional relationship between the rotational direction phase and the direction of the outer electrode. Assuming the use of a cylinder head at a specific position, the spark plug management gauge and the cylinder head plug hole management enable efficient quality control during the manufacture of plugs and cylinder heads. Gauges and their gauge sets.

  In the present invention, as described above, a so-called female gauge for a plug is first specified in advance in terms of the rotational direction phase of the threading start position of the external thread and the relative positional relationship between the rotational direction phase and the direction of the outer electrode. It is a screw ring-shaped spark plug management gauge used for quality control of spark plugs that are used, and a visible indicator that indicates the direction of the outer electrode when tightened to the spark plug thread with a specified torque. It shall be formed. The index is, for example, a two-sided width portion formed on the outer peripheral surface of the gauge body with a plane parallel to the direction of the outer electrode.

  In addition, the plug hole formed in the cylinder head is adapted to be fitted with a spark plug managed by the above-mentioned spark plug management gauge, and the so-called male gauge for the plug hole is described above. As shown above, the screw shaft-shaped plug hole management used for quality control of the plug hole in which the rotational direction phase of the threading start position of the female thread part on the plug hole side screwed into the male thread part on the spark plug side is specified in advance It is assumed that a visible indicator is formed to indicate the direction of the outer electrode when tightened with a specified torque with respect to the female thread portion of the plug hole. As an index, for example, a two-sided width portion formed on at least the outer peripheral surface of the shaft end of the gauge body with a plane parallel to the direction of the outer electrode is used.

  Of course, the index may be a marking, marking line, marking, or any other marking, instead of the width across flats.

  If these spark plug management gauges and plug hole management gauges are captured as a set, the internal thread of the spark plug management gauge and the threaded part of the plug hole management gauge are screwed together to provide the specified torque. It is assumed that the two-sided width part on the spark plug management gauge side that indicates the direction of the outer electrode and the two-sided width part on the plug hole management gauge side are both set in parallel when tightened with .

  According to the present invention, the spark plug in which the rotational direction phase of the threading start position of the external thread portion and the relative positional relationship between the rotational direction phase of the threading start position and the direction of the outer electrode are specified in advance, and the spark plug side In the quality control of the plug hole in which the rotational direction phase of the threading start position of the female thread part on the plug hole side to be screwed into the male thread part is specified in advance, it can be performed efficiently and quantitatively by a simple method, It can greatly contribute to the improvement of productivity.

The perspective view which shows the external shape of a spark plug as a more concrete form for implementing this invention. Cross-sectional explanatory drawing which shows schematic structure of the cylinder head with which the spark plug of FIG. 1 is mounted | worn. The enlarged view of the a part in the plug hole of FIG. Cross-sectional explanatory drawing which shows the state which mounted | wore the plug hole of FIG. 3 with the spark plug. FIG. 4 is an explanatory diagram of a plug management gauge for managing the plug shown in FIG. 1 and a plug hole management gauge for managing the plug hole shown in FIG. 3. FIG. 6A is a perspective view showing a relationship between the plug shown in FIG. 5 and a plug management gauge, and FIG. 6B is a perspective view showing a state where the plug management gauge is screwed to the plug. 5A is a perspective view showing the relationship between the plug management gauge and the plug hole management gauge shown in FIG. 5, and FIG. 5B is a perspective view showing a state in which the plug management gauge and the plug hole management gauge are screwed together. Figure. The perspective view which shows the relationship between the gauge for plug hole management shown in FIG. 7, and a plug hole. Explanatory drawing which shows the processing form of the seating surface of FIG. Explanatory drawing at the time of performing the tapping process of the internal thread part of FIG. 3 using a preset tapping tool. (A) is the principal part expansion schematic of the tap shown in FIG. 10, (B) is the detailed explanatory drawing. FIGS. 10A and 10B are diagrams illustrating a preset procedure of the preset tapping tool shown in FIG. 10, wherein FIG. 10A is an explanatory diagram when a tool presetter is calibrated using a bearing surface dedicated master gauge, and FIG. Explanatory drawing which shows the state which mounted | wore the gauge. Explanatory drawing of the bottom face of the tool holder in the preset tapping tool shown in FIG. FIGS. 10A and 10B are diagrams showing a preset tapping tool shown in FIG. 10 at the time of presetting, in which FIG. 10A is an explanatory diagram when making a standard using a master tap gauge and a locator, and FIG. Explanatory drawing which shows the state which removed. FIG. 15 is an enlarged plan view showing the relationship between the master tap gauge shown in FIG. 14A and a contact on the locator side. FIG. 11 is a diagram illustrating a preset procedure of the preset tapping tool illustrated in FIG. 10, and (A) is an explanatory diagram when the preset tapping tool of FIG. 10 is mounted on the tool presetter and positioning in the rotation direction is performed, (B) Fig. 4 is an explanatory diagram when setting the tool length of a preset tapping tool with a tool presetter. FIG. 17 is an enlarged explanatory view of a main part at the time of tool length preset shown in FIG.

  FIGS. 1 to 8 are views showing more specific forms for carrying out the present invention. In particular, FIG. 1 shows an external shape of a spark plug (hereinafter simply referred to as “plug”) 3 and FIG. -4 show the structure of the cylinder head 1 to which the plug 3 is attached. Further, FIG. 5 shows a schematic structure of a gauge used for quality control in each manufacturing process of the plug 3 and the cylinder head 1. The shape of the plug 3 in FIG. 5 schematically shows the shape of FIG.

  As shown in FIG. 1, the plug 3 manufactured as a mass-produced product by a plug manufacturer has a metal shell 4 formed with a large-diameter barrel portion 5 and a hexagonal portion 6 and adjacent to the barrel portion 5. A screw portion 7 is formed. Further, a gasket 8 is mounted in advance on the lower side of the neck of the body portion 5. The metal shell 4 faces the front end of the metal shell 4 so that the center electrode 32 protrudes, and a substantially L-shaped outer electrode (ground electrode) 33 that is paired with the center electrode 32 is provided on the metal shell 4. Yes.

  The plug 3 is tightened with respect to the internal thread portion 10 on the plug hole 2 side of the cylinder head 1 to be described later with the rotational direction phase (rotational direction position) of the threading start position of the external thread portion 7 and the specified specified torque. By managing the orientation of the outer electrode 33 (direction in which the outer electrode 33 is directed) at the manufacturing stage, the relative positional relationship between the two is determined in advance to be a specific positional relationship. The rotational direction phase of the threading start position of the threaded portion 7 and the direction of the outer electrode 33 at the time of tightening with the specified torque are matched in advance.

  On the other hand, as shown in FIGS. 2 and 3, the cylinder head 1 is provided with a stepped hole-like plug hole (plug hole) 2 that opens into the combustion chamber Q for each cylinder. Then, the plug 3 shown in FIG. 1 is mounted in the threaded form shown in FIG. The plug hole 2 on the cylinder head 1 side includes a small-diameter portion 2a close to the combustion chamber Q and a large-diameter portion 2b continuous therewith, and a seating surface 9 is formed at an intermediate portion between the two, and a female screw is attached to the small-diameter portion 2a. Part 10 is formed. Then, the plug 3 is fastened and fixed to the cylinder head 1 by the screwing action of the male screw portion 7 and the female screw portion 10 by tightening the plug 3 with a specified torque specified in advance, and the plug 3 side The body 5 is seated on the seating surface 9 via the gasket 8. As a result, the center electrode 32 of the plug 3 and the outer electrode (ground electrode) 33 paired with the center electrode 32 face the combustion chamber Q.

  In quality control of the manufactured plug 3, as shown in FIGS. 5 and 6, a screw ring-shaped spark plug management gauge having a female thread portion 40 a (hereinafter simply referred to as “plug management gauge”). 40 is used. The plug management gauge 40 is manufactured by, for example, transferring a plug 3 itself corresponding to a so-called mass production center product whose accuracy is finished to a median value of an allowable range as a master gauge, and having a predetermined thickness. The gage body 41 is formed with a female thread portion 41a that can be screwed with the male thread portion 7 on the plug 3 side, and a two-surface width portion serving as an indicator of the orientation of the outer electrode 33 described later on the outer peripheral surface. That is, a two-sided width portion 42 that is visible from the outside is formed.

  Then, when the plug management gauge 40 is screwed into the threaded portion 7 of the manufactured plug 3 with the gasket 8 and tightened with a specified torque, the direction of the outer electrode 33 that is the rotational direction phase ( The dihedral width portion 42 is formed so as to be parallel to the orientation direction of the outer electrode 33. The direction of the outer electrode 33 depends on the accuracy of the threading start position of the external thread portion 7, and a predetermined tolerance (tolerance) is given to the threading. Processed to the median difference. In addition, the code | symbol M of FIG. 5 has shown the position of the seating surface 9 in which the internal thread part 10 by the side of the cylinder head 1 shown in FIG.

  Therefore, when the manufactured plug 3 is completely inspected or removed, as shown in FIGS. 5 and 6, the plug management gauge 40 is screwed into the threaded portion 7 of the plug 3 with the gasket 8 as described above. Assume that the quality control is performed by evaluating whether or not the direction of the outer electrode 33 is parallel to the two-sided width portion 42 when tightened to a specified torque.

  On the other hand, the plug 3 in which the rotational direction phase of the threading start position of the external thread portion 7 and the relative positional relationship between the rotational direction phase and the direction of the outer electrode 33 is managed by the plug management gauge 40 is mounted. 2 to 4, the machining of the plug hole 2 in the manufacturing process of the cylinder head 1, particularly the tapping of the female thread part 10 of the plug hole 2, The rotation direction phase of the threading start position is managed to be a specific position.

  For quality control of the internal thread portion 10 in the plug hole 2 on the cylinder head 1 side, as shown in FIGS. 5 and 7, a screw shaft-shaped plug hole management gauge 43 having an external thread portion 43a is used. To do. The plug hole management gauge 43 is manufactured by using the plug management gauge 40 described above as a master gauge and transferring it with reference to the plug management gauge 40. The plug hole management gauge 43 is formed with a stepped shaft-shaped gauge body 44 composed of a large-diameter shaft portion 44a and a small-diameter shaft portion 44b as a main element. The small-diameter shaft portion 44b includes a large-diameter portion 44a. The same threaded portion 43a as the male threaded portion 7 on the plug 3 side is formed over a predetermined range on the side opposite to the large-diameter shaft portion 44a from the closest position. Further, two-sided width portions 45 and 46 that serve as indicators of the orientation of the outer electrode 33 to be described later, that is, two-sided width portions 45 and 46 that are visible from the outside, are formed at the shaft ends of the large-diameter shaft portion 44a and the small-diameter shaft portion 44b. It is.

  That is, as shown in FIG. 7, a screw ring-shaped plug management gauge 40 that functions as a master gauge of the plug hole management gauge 43 is connected to the actual plug 3 with respect to the screw shaft-shaped plug hole management gauge 43. When it is seated on the shoulder portion 47 (see FIG. 7A) of the large-diameter shaft portion 44a by tightening with the same specified torque, its direction (outer electrode) which is the rotational direction phase of the outer electrode 33 The two width portions 45 and 46 are formed so as to be parallel to the directivity direction (33). In other words, the two-sided width portion 42 of the screw ring-shaped plug management gauge 40 that functions as the master gauge of the plug hole management gauge 43 has the outer electrode 33 when tightened to the actual plug 3 as described above. 7 is set in advance so as to be parallel to the direction of the rotation direction (the direction of the outer electrode 33), as shown in FIG. When the gauge 40 is tightened with a specified torque and is seated on the shoulder 47 of the large-diameter shaft portion 44 a, the two-sided width part 42 of the plug management gauge 40 and the two-sided width parts 45, 46 of the plug hole management gauge 43. Are set to be parallel to each other.

  Therefore, in the inspection or sampling inspection of the plug holes 2 in the manufactured cylinder head 1, as shown in FIGS. 2, 3, and 8, the plug hole management gauge 43 to which the plug management gauge 40 is not screwed is shown. The single-sided width portion of the gauge 43 for plug hole management that becomes an index of the direction of the outer electrode 33 when it is screwed to the female screw portion 10 of the machined plug hole 2 and tightened to a specified torque in a single state. Assume that the quality control is performed by evaluating whether 45 and 46 are oriented in a specific direction.

  In this case, another jig that serves as a guide, for example, is connected to the two-sided width portion 46 of the plug hole management gauge 43 that faces the combustion chamber Q, and the outside is based on a specific position on the combustion chamber side. It is also possible to indicate the direction of the electrode 33 with an angle.

  As described above, the quality control of the plug 3 in which the rotational direction phase of the threading start position of the threaded portion 7 and the relative positional relationship between the rotational direction phase and the direction of the outer electrode 33 are specified in advance is used for screw ring-shaped plug management While the gauge 40 is used, the quality control of the plug hole 2 on the cylinder head 1 side, in which the rotational direction phase of the threading start position of the female thread portion 10 to which the plug 3 is to be mounted, is specified in advance. If the plug 3 is tightened to the plug hole 2 on the cylinder head 1 side with a specified torque specified in advance, the plug hole management gauge 43 is used to face the combustion chamber Q. The outer electrode 33 on the plug 3 side is always directed in the same specific direction. As a result, the quality control of the plug 3 and the plug hole 2 on the cylinder head 1 side where the plug 3 is used as a genuine part can be performed efficiently and quantitatively with a simple method, greatly contributing to the improvement of productivity. become able to.

  Next, a tapping process procedure for processing the female thread portion 10 in the plug hole 2 of the cylinder head 1 will be described.

  Most of the machining in the process of manufacturing the cylinder head 1 is performed by an NC type machine tool represented by a machining center, and particularly includes the small diameter portion 2a and the large diameter portion 2b shown in FIGS. When attention is paid to the processing procedure of the plug hole 2, the cutting of the seating surface 9 and the threading of the female thread portion 10 are performed after the cutting of the small-diameter portion 2a and the large-diameter portion 2b as pre-processing. The threading of the female thread portion 10 is performed by tapping, that is, tapping. Both the cutting process of the seating surface 9 and the tapping process of the internal thread portion 10 are performed using a common machining center which is an NC type machine tool, and the cutting process of the seating surface 9 is performed as a counterbore as a pre-processing. Subsequently, the tapping process of the female screw portion 10 is performed.

  The seating surface 9 is processed by mounting a counterbore cutter 11 as shown in FIG. 9 on the spindle of the machining center. The counterbore cutter 11 is a general-purpose HSK type tool holder 12 that supports a counterbore cutter 13 so as to be detachable. The counterbore cutter 13 is, for example, two throwaway type chamfers at the body tip. A chip 13a is attached. Then, while the counterbore cutter 11 is rotated at a predetermined speed, a cutting feed in the axial direction is given to the counterbore cutter 11 to perform a counterbore with a part of the chamfering to finish the seating surface 9 with a predetermined accuracy.

  The counterbore cutter 11 has a tool length when it is mounted on the spindle of the machining center, preset in advance using a known tool presetter, which will be described later, in a so-called external preset method to a specified dimension.

  On the other hand, the tapping process of the female thread portion 10 is performed by attaching a preset tapping tool 14 as shown in FIG. 10 to the spindle of the machining center. The preset tapping tool 14 is a general-purpose HSK type tool holder 15 which is supported by a tap 16 so as to be detachable as described above. A long shank tap type is used. Then, using the tapping process mode of the machining center, a pitch feed for tapping is given to the preset tapping tool 14, and the female thread part 10 is machined by using the small diameter part 2a as a screw pilot hole by a so-called one-pass method. 11A shows the outline of the threaded portion 17 of the tap 16, and FIG. 11B shows the details of the threaded portion 17. In FIG. 2B, T1 is a complete (thread) thread portion and T2 is a biting portion.

  In this case, if a position that is a predetermined distance L (known value) away from the seating surface 9 that has been previously cut is the pitch feed start position M for tapping, the seating surface 9 is open. The preset tapping tool 14 is approached to the pitch feed start position M toward the small-diameter portion 2a as a screw pilot hole, and the preset tapping tool 14 is positioned in the rotational direction at the pitch feed start position M. It is assumed that pitch feed for tapping is started.

  In addition, since the tool for tapping is the preset tapping tool 14, the tool holder 15 supporting the tap 16 is correctly attached to the spindle of the machining center only after the rotation direction position is determined at a specific position. Therefore, as described later, in managing the phase of the threading start position of the female thread portion 10, the rotational direction position of the tap 16 with respect to the tool holder 15 is indexed to a specific position by a so-called external preset method. Based on being preset. At the same time, based on the fact that the tool length when the preset tapping tool 14 is mounted on the spindle of the machining center is preset to a prescribed dimension by a so-called external preset method using a known tool presetter as will be described later. Yes.

  Both the counterbore processing of the seating surface 9 and the tapping processing of the female thread portion 10 are performed by using a machining center which is a common NC type machine tool, and the cylinder head 1 which is a workpiece to be processed is used as the machining center. Once the workpiece table is clamped, counterbore processing and subsequent tapping processing are performed at once by a so-called 1 clamp (1 chuck) system. That is, the cylinder head 1 is subjected to the tapping process following the counterbore process without being unclamped from the work table even after the counterbore process is finished. At the same time, if spot facing of the seating surface 9 is performed using, for example, the Z axis of the machining center, the subsequent tapping process is also performed using the same Z axis.

  As described above, the spot face machining and the tapping are performed on the plug hole 2 of the cylinder head 1 by the so-called one-clamp method using the same machining axis of the same machining center. Since there is a large correlation with the accuracy of the phase (position in the rotational direction) of the threading start position of the threaded portion 10, the plug hole 2 is used as described above in order to improve the phase accuracy of the threading starting position of the female threaded portion 10. This is because it is important that the counterbore processing and the tapping processing are performed on the same processing standard.

  Here, so-called external presetting of the preset tapping tool 14 using a known tool presetter (for example, TP-400 manufactured by Nippon ID System Co., Ltd.) is performed in the following procedure.

  First, as shown in FIG. 12 (A), the tool presetter is calibrated using a seating surface dedicated master gauge 18 for processing the seating surface 9 prepared in advance. 9 is a master bar having the same diameter and the same length as the counterbore cutter 11 shown in FIG. 9, and is used to preset the tool length of the counterbore cutter 11 shown in FIG. It is.

  This seat surface master gauge 18 is set on the spindle of the tool presetter, and the seat surface master gauge is used with the enlargement projection function by the tool presetter projector (may be the imaging enlarged display function by the CCD camera). The shape of the tip of 18 is projected, and a reference line as an index on the screen, that is, two cross-shaped reference lines 19a and 19b orthogonal to each other are respectively provided on the gauge tip surface and the cylindrical surface of the master gauge 18 for the seating surface. Calibrate to match. In addition, on the screen of the projector, apart from two orthogonal reference lines 19a and 19b, two reference lines 20a corresponding to a complete (thread) thread portion of the thread portion of the tap 16 as described later. , 20b are preliminarily displayed in a mountain shape.

  As described above, in this calibration, the positional accuracy of the seating surface 9 in the plug hole 2 has a large correlation with the accuracy of the phase (position in the rotational direction) of the threading start position of the female screw portion 10, and the female screw portion This is performed in order to improve the phase accuracy of the 10 threading start positions, that is, to eliminate the angle error. That is, it is important to preset the counterbore cutter 11 for processing the seating surface 9 and the preset tapping tool 14 for tapping the internal thread portion 10 on the same basis. However, this calibration work can be omitted if the tool presetter alone is sufficiently calibrated.

  When calibration is completed, the bearing surface master gauge 18 is removed from the spindle of the tool presetter, and instead, the master tap gauge 21 is set on the spindle of the tool presetter as shown in FIG. The master tap gauge 21 is the same as the preset tapping tool 14 (including the tool holder 15) for actual machining shown in FIG. 10, and is stored as a master gauge and not used for actual machining. is there. Then, as the posture of the master tap gauge 21 set on the spindle of the tool presetter, the posture equivalent to that when the preset tapping tool 14 is mounted on the spindle of the machining center as shown in FIG. 10 is reproduced.

  More specifically, as shown in FIG. 13, when the preset tapping tool 14 is mounted on the spindle of the machining center, the key block 23 is fitted into the groove portion 22 of the tool holder 15 to perform positioning in the rotational direction. At the same time, the information on the ID chip 24 is read and written between the ID chip 24 attached to the tool holder 15 and the ID chip sensor 25 on the spindle side. Accordingly, similarly for the master tap gauge 21, as shown in FIG. 12B, a slidable key block 26 prepared in advance on the tool presetter side is fitted into the groove 22 of the tool holder 15. The positioning in the rotational direction is performed in the same manner as when the spindle is mounted on the machining center side. At the same time, necessary information is exchanged between the ID chip sensor similar to that shown in FIG. 13 and the ID chip 24 prepared in advance on the tool presetter side. As a result, on the tool presetter, the positioning of the master tap gauge 21 in the rotational direction with respect to the key block 26 is performed under the same conditions as when the spindle on the machining center side is mounted.

  In this way, when the master tap gauge 21 set on the spindle of the tool presetter is positioned in the rotational direction, the threaded portion of the tap 27 in the master tap gauge 21 as shown in FIG. The contact 29 of the locator 28 is lightly applied to the rake face 27a to create a reference for the rotational direction at the tip of the tap 27 of the master tap gauge 21. The locator 28 has a flat contact 29 attached in a cantilevered state from the upper end of the magnet stand 30. If the reference can be established by the contact of the contact 29 with the rake face 27a, the magnet stand The magnetic stand 30 is attracted and fixed to the non-movable part of the tool presetter by the magnetic force of 30.

  Subsequently, the master tap gauge 21 is removed from the spindle of the tool presetter as shown in FIG. 14B, taking care not to change the position of the locator 28. Instead, as shown in FIG. 16A, the preset tapping tool 14 before the preset for actual tapping is set on the spindle of the tool presetter. As in the case of the master tap gauge 21, the slidable key block 26 prepared on the tool presetter side is fitted into the groove 22 (see FIG. 13) of the tool holder 15 so that the machining center side Positioning in the rotational direction is performed in the same manner as when the main shaft is mounted. At the same time, necessary information is exchanged between the ID chip sensor 25 and the ID chip 24 (both see FIG. 13) prepared in advance on the tool presetter side. As a result, the positioning of the preset tapping tool 14 in the rotational direction with respect to the key block 26 is performed under the same conditions as when the spindle on the machining center side is mounted.

  Here, the preset tapping tool 14 is positioned in the rotational direction of the tool holder 15 with reference to the key block 26 attached to the tool presetter. The most functionally important tap 6 rotation direction and tool length setting remain incomplete.

  Therefore, when the tap 16 is unchucked with respect to the tool holder 15 of the preset tapping tool 14 and the tap 16 is appropriately rotated to position the tap 16 in the rotational direction, the case shown in FIG. Similarly, the rake face 16a of the threaded portion of the tap 16 is lightly applied to the contactor 29 of the locator 28, and the contactor 29 of the locator 28 is placed on the raked face 27a of the threaded portion of the tap 27 in the previous master tap gauge 21. Reproduce the lightly touched state. Accordingly, at least the positioning of the tap 16 in the rotation direction in the preset tapping tool 14, that is, the rotation direction phase of the tap 16 is determined. In addition, about the square part of the shank rear end of the tap 16, the rotation prevention function is made not to be exhibited.

  Subsequently, the tool length of the tap 16 in the preset tapping tool 14 is set. When the tool length of the tap 16 is set, if the tip surface of the tap 16 is used as a reference, the processing accuracy of the tip surface is not higher than the function of the tap 16, so that the tap 16 is used as described above. This is insufficient for managing the rotational direction phase of the threading start position of the female thread portion 10 to be processed.

  Therefore, in the present embodiment, when setting the tool length of the tap 16 in the preset tapping tool 14 (preset), the idea is greatly changed, and the complete (thread) thread of the thread portion 17 having a high machining accuracy among the taps 16. It is assumed that the flank of the specific mountain of the portion T1 (see FIG. 11) (the inclined surface connecting the crest and the valley bottom of the screw portion) is used as a reference.

  More specifically, as shown in FIG. 16B, a preset tapping tool 14 is used by using an enlargement projection function by a projector of a tool presetter (an imaging enlargement display function by a CCD camera may be used). The shape of the tip of the tap 16 is projected, and the reference lines 20 a and 20 b that are indices on the screen are superimposed on the tip of the tap 16. It should be noted that, in addition to the two cross-shaped reference lines 19a and 19b orthogonal to each other, two reference lines 20a and 20b having a mountain shape are displayed in advance on the screen of the projector. . The angle formed by the two reference lines 20a and 20b forming the mountain shape is made to coincide with the angle α formed by the flank on both sides of the complete (thread) thread portion T1 of the tap 16, as will be described later.

  As described above with reference to FIG. 11, the screw portion 17 of the tap 16 includes a biting portion T2 on the tip side and a complete (thread) thread portion T1 that follows, and the biting portion T2 is incomplete (screw). Yamabe. FIG. 17 is a further enlarged view of FIG. 11B. In the example of FIG. 17, the third peak 17a from the tip end side of the tap 16 is the first peak of the complete peak T1, and the subsequent steps are completely complete. The second mountain 17b of the mountain T1, the third mountain 17c of the complete mountain T1, and so on. As described above, the size (T2 itself) of the biting portion T2 that is an incomplete screw portion has a large variation and is not suitable for the reference of the tool length of the tap 16. The two reference lines 20a and 20b having the mountain shape on the screen side of the projector described above are displayed on the flank on both sides of each mountain 17a, 17b... (Inclined surface connecting the top of the thread and the bottom of the thread) 31 and 31 are made to coincide with each other in advance.

  When the reference lines 20a and 20b, which are indices on the screen of the projector, are superimposed on the projected shape of the tip portion of the tap 16, as shown in FIG. 17, the mountain shape is formed on the flank 31 of the first mountain 17a of the complete mountain portion T1. A pair of reference lines 20a and 20b that are formed so as to overlap each other and set so that the tool length becomes a predetermined dimension, that is, preset, and in that state, a chuck (not shown) built in the tool holder 15 is mounted. And chucking firmly. This is because the line that bisects the angle α between the flanks 31 of the specific peak 17a of the complete peak T1 is the horizontal reference line 19a, and therefore one peak of the complete (thread) peak T1. The matching of the pair of reference lines 20a and 20b having a mountain shape with the flank 31 of the eye peak 17a is based on the assumption that the peak of the peak 17a has an acute angle. There is nothing else. Thus, the preset operation of the preset tapping tool 14 is completed. It is also possible to use the second mountain 17b and the third mountain 17c instead of the first mountain 17a of the complete mountain portion T1.

  In this case, the intended purpose cannot be achieved with a chuck that slightly pulls the tap 16 toward the tool holder 15 during chucking, and therefore the tap is not pulled even if a clamping force is applied due to chucking. For example, a milling chuck or the like is adopted. Also, when setting the tool length of the tap 16, the intersection of the cross-shaped reference lines 19a, 19b is not directly matched with the tops of the peaks 17a, 17b ... Since it is a cylindrical surface when viewed microscopically as shown in FIG. 17, even when setting using a projector, the intersection of the cross-shaped reference lines 19a and 19b can be made to exactly match the cylindrical surface. It is difficult.

  As is clear from the above description, when presetting the preset tapping tool 14, the tool presetter is first calibrated by using the bearing surface master gauge 18 for presetting the tool length of the counterbore cutter 11, and then, Using the calibrated tool presetter, the preset tapping tool 14 is positioned in the rotational direction and the tool length is preset. This means that the counterbore cutter 11 for machining the seating surface 9 in the plug hole 2 and the preset tapping tool 14 for machining the internal thread portion 10 in the plug hole 2 are the same machining axis (Z Assuming that it will be used for machining on the axis), it is nothing but a preset based on the same standard.

  Then, the counterbore processing of the seating surface 9 is performed in the form of FIG. 9 using the counterbore cutter 11 preset with reference to the master gauge 18 for the seating surface. The depth) is managed by the dimension management function of the machining center itself.

  On the other hand, the tapping process of the female thread portion 10 following the counterbore process of the seating surface 9 is performed in the form of FIG. 10 using the preset tapping tool 14 preset by the procedure described above. In this case, a position that is a predetermined distance L away from the seating surface 9 that has been subjected to spot facing is set as a pitch feed start position M, and this pitch feed is started toward the screw pilot hole 2a that opens in the seating surface 9. As described above, the preset tapping tool 14 is approached to the position M, the positioning of the preset tapping tool 14 in the rotational direction is performed at the pitch feeding start position M, and then the pitch feeding for tapping is started. It is. The reference position on the preset tapping tool 14 side with respect to the predetermined distance L is the first peak 17a in the complete peak T1 of the tap 16 described above.

  Then, in a state where the preset tapping tool 14 is approached to the pitch feed start position M and positioning in the rotational direction is performed at the pitch feed start position M, the predetermined distance L has a specified dimension and the tap 16 The rotational direction phase is determined at a specific phase angle position. Therefore, when the pitch feed for tapping is started from the pitch feed start position M, the tap 16 enters the screw pilot hole 2a by the screwing action of the screw and is n-th rotation from the pitch feed start position M and The threading of the screw thread portion 10 is started from a specific phase angle position of the n-th rotation, and finally the through hole type female screw portion 10 is finished. This means that the threading of the threaded portion 10 starting from the specific phase angle position of the n-th rotation from the pitch feed start position M can be similarly reproduced regardless of how many times tapping is repeated. Means.

  In other words, the counterbore process of the seating surface 9 and the tapping process of the female thread portion 10 are performed using the same machining axis (Z axis) of the same machining center, and the cylinder head 1 between the counterbore process and the tapping process. Assuming that the internal thread portion 10 of the plug hole 2 for the n cylinders of the cylinder head 1 is processed with the common preset tapping tool 14 on the assumption that the cylinder is not detached and attached, the seating surface for each cylinder 9 are all the same specific phase angle positions. This does not change even if the same processing is performed one after another in the mass production processing line of the cylinder head 1.

  When the plug 3 is attached to the plug hole 2 of each cylinder of the cylinder head 1 processed in this way as shown in FIG. 4, the start of the male threaded portion 7 on the metal shell 4 side of the plug 3 as described above. If the relative positional relationship between the position (the rotational direction phase of the threading start position of the external thread portion) and the outer electrode 33 is managed to be a specific positional relationship, that is, the threading start position of the external thread portion 7. If the rotation direction phase of the plug 3 and the direction of the outer electrode 33 when the plug 3 is tightened with a specified torque are matched in advance, the plug 3 is fixed to the female thread portion 10 of the plug hole 2 with a predetermined torque. It is possible to always adjust the outer electrode 33 to a specific direction (rotational direction position) in any cylinder by simply tightening the. As a result of the trial production by the present inventors, it was confirmed that the outer electrode 33 can be managed at about ± 10 ° with respect to the target specific direction.

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 2 ... Plug hole 2a ... Screw pilot hole 3 ... Spark plug 7 ... Male thread part 9 ... Seating surface 10 ... Female thread part 14 ... Preset tapping tool 15 ... Tool holder 16 ... Tap 16a ... Rake face 17 ... Screw Part 17a ... First mountain 31 ... Frank 33 ... Outer electrode 40 ... Spark plug management gauge 41 ... Gauge body 42 ... Two-sided width part (index)
43 ... Gauge for managing plug hole 44 ... Gauge body 44a ... Large diameter shaft portion 44b ... Small diameter shaft portion 45 ... Two-sided width portion (index)
46 ... Width across flats (index)
T1 ... Complete Yamabe

Claims (8)

A thread ring-shaped spark plug used for quality control of a spark plug in which the rotational direction phase of the threading start position of the external thread and the relative positional relationship between the rotational direction phase of the threading start position and the direction of the outer electrode are specified in advance. A management gauge,
A gauge for managing a spark plug, characterized in that a visible indicator is formed to indicate the direction of the outer electrode when tightened with a specified torque with respect to the threaded portion of the spark plug.   2. The spark plug management gauge according to claim 1, wherein the index is a two-sided width portion formed on an outer peripheral surface of the gauge body with a plane parallel to the direction of the outer electrode. A spark plug managed by the spark plug management gauge according to claim 1 or 2 is mounted in the plug hole formed in the cylinder head, and is screwed into the male thread portion on the spark plug side. A screw hole-shaped gauge for plug hole management used for quality control of a plug hole in which the rotational direction phase of the threading start position of the female thread part on the plug hole side to be combined is specified in advance,
A gauge for plug hole management of a cylinder head, characterized in that a visible indicator for instructing the direction of the outer electrode is formed when the female screw part of the plug hole is tightened with a specified torque.   For a stepped shaft gauge body consisting of a large-diameter shaft portion and a small-diameter shaft portion, a male thread portion is formed over a predetermined range on the side opposite to the large-diameter shaft portion from a position closest to the large-diameter shaft portion among the small-diameter shaft portions. The gauge for plug hole management of a cylinder head according to claim 3, wherein   5. The plug hole management gauge for a cylinder head according to claim 4, wherein the plug hole management gauge is manufactured based on a master gauge.   6. The cylinder head plug hole management gauge according to claim 5, wherein the master gauge is the spark plug management gauge according to claim 2.   7. The gauge for plug hole management of a cylinder head according to claim 6, wherein the index is a two-sided width portion formed on at least the outer peripheral surface of the shaft end of the gauge body with a plane parallel to the direction of the outer electrode. . A gauge set comprising the spark plug management gauge according to claim 2 and the plug hole management gauge according to claim 7,
Two surfaces on the spark plug management gauge side that indicate the direction of the outer electrode when the female screw part of the spark plug management gauge and the male thread part of the plug hole management gauge are screwed together and tightened to the specified torque. A gauge set, characterized in that the width portion and the two-side width portion on the gauge side for plug hole management are set to be parallel to each other.

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